Introduction: Acrylic Bender From Laser Printer With Relay Timer Box
A simple acrylic heat bender from an old laser printer, some reclaimed marble tiles, a lamp dimmer, and some other scrap parts.
A laser printer uses a radiant heat lamp to heat the paper and set the toner. They are easily found and harvested, had one laying around for months until I saw another acrylic bender that used one for the heat source. Its not very big/wide, but suitable for many projects.
The marble tiles offer a flat smooth, heat safe surface. And the idea was they would dissipate the heat away from the bending area, allowing a sharper bend. Its recommended to use a water cooled base, but that would be more effort than is needed to do the occasional acrylic bending.
THIS PROJECT USES A.C. MAINS AND IS EXTREMELY DANGEROUS. RECREATE AT YOUR OWN RISK!
Step 1: Supplies and Tools
- Radiant heat lamp from a laser printer
- Plywood base, used marine grade for strength and stiffness
- Aluminum U channel, used a scrap a bit longer than the heat lamp
- AC cord, can cut them off any discarded electronics
- Acrylic or high impact styrene, to make the covers
- Halogen dimmer, reclaimed from a standing lamp, part# SC237
- Marble Tiles, found in the trash
- Drill and bits
- Table saw or chisel to make the dado
- Hack saw, to cut aluminum
Optional Relay Timer:
- External 3-Digit LED Display - www.NLEDshop.com
- 5v relay, 120v/250v 15A rating
- Flyback/Snubber Diode for relay , 1N4007 used, but many could work
- Plastic Outlet Box, regular one from home depot
- 5 volt power supply, used an old cell phone charger(before micro USB), 200mA would be enough
- Momentary push button, normally open. Larger one easy to press
- 3-prong Single A.C. Outlet (found surplus)
- C14 Cord outlet(same as PC Cable, surplus from an old PC power supply)
- Misc soldering supplies
- Hot Glue Gun and Sticks
Step 2: Prepare the Base Plate
- Cut the plywood base to size after a rough test fit of everything.
- Marked the center groove, marked either side to make a 0.75" wide dado.
- Setup the table saw and used scrap lumber to setup the depth. The depth was chosen so the U channel that holds the heat lamp will be just a tad shorter than the tiles, so the aluminum U channel won't touch the material that is being bent.
- Cut the dado using multiple passes in with the table saw.
- Cleaned up the groove with a sharp chisel.
Prepare the U Channel:
- As pictured, a vice was used to squeeze a metal bar(taken from a printer) into the U channel, flaring it wider.
- Hit it with a hammer as well to really flare it open
- Drilled 2 holes for small screws on either end
- Countersunk the holes
- Mounted the U channel on center, and screwed it down with v neck screws(that fit into the countersink)
Mount Marble Tiles: Used the marble tiles as they were free, flat, smooth, and sink heat decently. Ideally acrylic benders use water cooling near the bend line to create crisper bends. But as long as this bender isn't used to many times in a row, it does a very good job at producing sharp bends.
- Used some heavy beads of a good construction adhesive(flexible kind) to mount the marble tiles to the plywood base.
- Position them so they are flush with the U channel and on center.
- Pressed them down real good and let dry.
Heat Lamp Power Input: Simple brackets with adjustment screws are used to clamp the bulb and give it AC power. This relies on the electrical insulation of the wood. So it may be wise to add additional insulation.
- 2x 0.5" longs of the same U channel was cut
- Drilled hole in the bottom for mounting
- Drilled and tapped a 6-32 holes all the way through
- Mounted the brackets approx 0.25" away from the heat lamp contact
Step 3: Wiring
Wiring: The radiant heat lamp is not polarized so doesn't matter which side is live or neutral, but the halogen lamp dimmer is. Mind the polarization.
- Found a surplus 2-prong A.C. cord to use.
- Hooked up the A.C. live through the lamp dimmer(as per instructions), and the neutral to one side of the heat lamp through the bracket.
- Hooked up the lamp dimmer A.C. live output to other bracket for the heat lamp.
- Used the adjustment screws on the brackets to carefully mount the heat lamp. Don't over tighten the screws or it will break the heat lamp.
- Tested it
Covers: Now that it is working it can be used to finish making itself.
- High impact styrene was cut to size, 2 pieces to cover the brackets, 1 piece to cover the dimmer, and one larger piece that will cover the lamp when the bender is being stored.
- Used the bender to bend the bracket and dimmer covers to suit.
Step 4: Relay Timer With LED Display
An optional addition but very helpful, used a product from www.NLEDshop.com. The External 3 Digit LED Display was selected to make simple relay timer. The firmware is available for download from the website and it was edited to allow the user to set the desired ON time(using the 2 buttons). Then when the added third button is pressed, it will turn on an outlet(that the acrylic bender is plugged into) and leave it on for the desired time then turn off. If the button is pressed while the relay is on, it will turn it off.
Didn't originally expect to share this, but it is very handy for acrylic bending and I am sure other projects in the future. So I decided to share it.
This part also uses A.C. Mains and is extremely dangerous, do not attempt!
- External 3 Digit LED Display(Pulled the connection Header) - www.NLEDshop.com
- C14 Outlet, surplus
- Single outlet, surplus
- Single outlet wall electrical box
- 5v cell phone charger
- 120v/250v, 15A relay, normally open
- Momentary push button, with mounting tabs
Not going to cover the assembly as the schematic and parts list tells it all. Fairly easy to make, except for having to pull the LED displays header(required a hot air gun) and to add the extra parts, such as the 10k pullups to the LED display PCB. Lots of hot glue to keep it together and prevent any wires from coming loose.
Works great, all you do is position the acrylic on the bender, press the button, work on something else til the relay clicks and the light turns off, then bend. Saves a lot of time and effort that was being spent watching a stop watch.
Step 5: All Done
All done and ready to use. This already has quite a bit of miles on it, and it works quite well. Usually use a granite countertop sample(4"x4") to help with the bending, also works well cause it sucks the heat right out of the bent acrylic, so it sets faster. And is perfectly square on all sides, and smooth on one side.
One drawback is the lamp is very bright when it is on. Usually have to place a scrap of aluminum bar over the part of the heat lamp that isn't being used for bending. If done over again would have added some simple water cooling by placing some aquarium or similar tubing under the granite tiles and setting them with some sort of plaster or cement.
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Please be positive and constructive.